Chapter 10 1 james hutton the father of geology put forth the principle of a superposition b original continuity c original horizontality d uniformitarianism 2 as understood by modern geologists the principle of uniformitarianism implies that a the earth has always had the same basic appearance that it has today which the distributions of ocean basins and continents identical to what we see today b igneous metamorphic and sedimentary rocks are uniformly mixed throughout the crust of the earth c physical processes observed today such as erosion and volcanic eruption have been active in the past and are responsible for the geologic history we see preserved in the rock record d physical processes observed today such as erosion and volcanic eruption have been occurring throughout earth history at constant rates for example no eruption in geologic time would have been greater than the 1815 tambora eruption 3 in an undisturbed sequence of sedimentary rocks younger layers overlay older layers according to the principle of a superposition b original continuity c original horizontality d uniformitarianism 4 if the lithology and fossil content of two bodies of rock on opposite sides of a canyon are identical then these remaining outcrops were likely physically connected at one time and formed part of an extensive sheet like layer of rock This idea summarizes the principle of a superposition b original continuity c original horizontality d uniformitarianism 5 which of the following geologic principles is a direct result of gravity a baked contacts b cross cutting relationships c original horizontality d inclusions 6 relative ages expressed on the geologic time scale primarily resulted from the study of a fossil content and spatial relationships among igneous rocks b fossil content and spatial relationships among sedimentary rocks c radiometric dating of igneous rocks d radiometric dating of sedimentary rocks 7 numerical ages for boundaries between time units on the geologic time scale primarily resulted from the study of in conjunction with relative age data a fossil content and spatial relationships among igneous rocks b fossil content and spatial relationships among sedimentary rocks c radiometric dating of igneous rocks d radiometric dating of sedimentary rocks 8 within the world s sedimentary rocks fossils a are rarely if ever found b are randomly distributed c occur in an ordered sequence 9 if horizontalsedimentary strata overlie tilted strata and no fault is present the surface between the horizontal and tilted strata must be a n a conformable sedimentary contact b angular unconformity c disconformity d nonconformity 10 the surface below sedimentary rocks that overlie igneous or metamorphic rocks is termed a n a disconformity b angular unconformity c nonconformity 11 buried erosional surfaces between parallel sedimentary strata are termed a disconformities b angular unconformities c nonconformities 12 which method of correlation is more reliable for determining relative ages of rock units over broa area a lithologic correlation b fossil correlation 13 two atoms of a single element that differ in number of neutrons are said to represent two distinct of that element a isomers b isotopes c isotherms d atomic species 14 which of the following is always the same for multiple isotopes of a single element a atomic number b atomic mass number c tendency to decay radioactively d none of the above 15 which of the following always varies among multiple isotopes of a single element a atomic number b atomic mass number c tendency to decay radioactively d none of the above 16 which proportion of a radioactive isotope is expected to remain in an unreacted state after the passage of three half lives a one third b three halves c one eighth d one sixth unaltered 17 in an unweathered sample of igneous rock the ratio of an unstable isotope to its stable daughter isotope is 1 15 If no daughters were present at the time the rock cooled and the half life of thereaction is 50 million years how old is the rock a 200 million years b 400 million years c 750 million years d none of the above 18 in an unweathered sample of detrital sedimentary rock the ratio of an unstable isotope to its stable daughter isotope is 1 15 If no daughters were present at the time the rock cooled and the half life of the reaction is 50 million years how old is the rock a 200 million years b 400 million years c 750 million years d none of the above 19 radiometric dates appliedto sedimentaryrocks produce ages that are a just as accurate as when the technique is appliedto igneous rocks b too young postdate sedimentary deposition c too old predate sedimentary deposition 20 which statement best summarizes the development of the geologic time scale a numerical ages for rocks were known well before the relative sequence of sedimentary layers was established b relative ages for sedimentary strata were known well before accurate numerical dates for these rocks could be provided c names of relative ages such as silurian and accurate numerical dates for these ages appeared at about the same time 21 radioactive decay provides the internal heat of the earth a true b false 22 if the numerical ages of two formations are known then the relative age of each with respect to one another can be inferred a true b false 23 if the relative age of two formations with respect to one another is known then the numerical ages for each formation can be inferred a true b false 24 in the area immediately surrounding an igneous intrusion a host limestone is locally metamorphosed to produce marble Which of the following statements is correct a the intrusive igneous rock must be older than the limestone given b the limestone must be older than the marble c the marble must be older than the intrusive rock d the relative ages of the three units cannot be determined with the information 25 the earth isapproximately 4 6 billion years old a true b false 26 the surfaces named contacts 2 and 3 are examples of a conformable sedimentary contacts b faults c baked contacts d unconformities 27 contact 1 is an example of a n a conformable sedimentary contacts b faults c baked contacts d unconformities 28 the oldest geologic unit in the cross section is the a granite b marble c limestone d sandstone 29 the youngest geologic unit visible in the cross section is the a granite b limestone c conglomerate d marble 30 the marble rind surrounding the granite pluton must be younger than